If you take up the suggestions here you will need to convince me that you are not abusing an important identifier and that you can protect my data. My default

If you take up the suggestions here you will need to convince me that you are not abusing an important identifier and that you can protect my data. My default answer for most sites is that I don't trust you with my phone number (e.g. Facebook using recovery phone as an undisclosed identifier) and certainly not my credit card number in some random database.